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Total Serum Immunoglobulin G (IgG) Level

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of Immunoglobulin G (IgG), the most common type of antibody in your blood. IgG helps protect your body from infections and is important for long-term immunity.

Quick summary

["IgG helps fight infections and supports long-term immunity by marking pathogens for destruction."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
109056-2
Short code
tTG IgG Msmt Ser
Synonyms
tTG IgG Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Does This Test Measure?

IgG is a type of protein (antibody) produced by your immune system to help fight infections. Your body makes IgG in response to bacteria, viruses, and other foreign substances. This test checks the total amount of IgG in your serum, which can help doctors assess your immune system’s strength and detect conditions like immunodeficiency or certain infections.

Why Might You Need This Test?

Doctors may order an IgG test if you have symptoms of a weakened immune system (such as frequent infections), if you’ve had a recent infection, or if you’re being evaluated for conditions like HIV, lupus, or other autoimmune diseases. It can also be used to monitor treatment progress for certain immune-related conditions.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood, which usually causes only minor discomfort. If you’re nervous, let your healthcare provider know so they can help make the process more comfortable.

What to Expect During the Test

The blood sample will be sent to a lab for analysis. Results are typically available within a few days, depending on lab processing times. Your doctor will discuss the results with you and explain any follow-up steps needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

How low or high IgG levels might affect your health?
Low IgG levels could indicate a weakened immune system, which may increase your risk of infections. This can happen in conditions like HIV, certain autoimmune diseases, or after treatments like chemotherapy. High IgG levels may suggest an overactive immune response, such as in chronic infections or certain cancers.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition, symptoms, and treatment plan. Some people may need it once or twice a year, while others may need it more frequently if they’re undergoing treatment for an immune-related condition.
Can I eat or drink before this test?
You can eat and drink normally before this test, as no special diet is required. However, if you’re taking any medications that might affect blood tests, let your doctor or lab technician know before your appointment.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy